Burn-in (i.e. a test where an electronic device such as e.g. a circuit, system or component is run for a certain period of time to detect problems) may be mandatory for certain electronic products for the automotive sector. For instance, for MCUs with embedded flash memories, 100% full time burn-in may be a requirement.
Burn-in may be a fairly expensive step, and a test strategy, e.g. a MCU test strategy, may provide that certain elements of the burn-in infrastructure (e.g. the burn-in boards (BIBs), the BIB Loader Unloader (BLU), and possibly the climatic chambers) should be re-usable in order to increase the lifetime of all necessary items. The cost of testing may thus be reduced by applying the flash test (which may be long, e.g. several tens of seconds per unit) on the test step having the highest parallelism.
BIBs may be equipped with integrated circuit (IC) sockets having e.g. a cost in the range of $30-$60 with through-hole mounting (soldered). Such BIBs may exhibit a certain sensitivity to ageing (contact resistance or Cres, mechanical degradation of the plastic frame, springs and contact leads). Also, they may be monolithic, and thus customized for each product/package type.
These BIBs may thus exhibit performance degradation through ageing, due to their being “burned” several times together with the devices (e.g. ICs) undergoing burn-in. This performance degradation may have an impact in terms of yield with false fails and damaged BIB components (sockets, passive), which may not be replaceable due to their being soldered on the printed circuit board (PCB) of the BIB via through holes. A BIB may thus be scrapped once its overall performance level drops below a defined threshold to be replaced with a new one.
Also, conventional BIBs may be customized on a product/package basis, so that non-recurring engineering or effort (NRE) may be desired for each new product, possibly along with debugging and validation of the new hardware (HW) associated therewith. In order to temporarily recover some of the performance level, BIBs may be cleaned using chemicals. These may be unfriendly to the environment, and the associated processing step may have a cost which impacts on the overall cost of ownership (COO).